The present invention relates to an electrically operated domestic water distilling apparatus. It relates particularly to a distilling apparatus operating at a small over-pressure, so designed as to permit ready cleaning of the evaporation chamber and of the electric heating element.
It has long been recognized that the drinking water in many communities has an unpleasant taste due to chlorine, minerals, or suspended organic matter. Such water may also contain chemicals, bacteria, or other contaminants believed to endanger health. This condition, widely publicized in recent years, has become much more acute due to the proliferation of chemical wastes. In some communities, residents will not drink the water, and have either resorted to purchasing bottled water (generally expensive), or have installed central water purifying plants or distilling apparatuses.
All known water distillers prior to the present invention comprise a closed evaporation chamber, a heating element located near the chamber bottom, a stream outlet located near the top of the chamber and leading to a usually finned condenser coil, and a fan which blows fresh air over the condenser surface. The evaporation chamber is usually removable so that it can be filled with raw water, and so that residues and sediments can be removed.
The main problems incurred with all distilling apparatuses of the prior art are:
1. The need to clean the bottom of the evaporation chamber from sediments, requiring disassembly of the whole chamber or its lower portion, and which may be heavy with contaminated raw water; the chamber must be reassembled, a process which is often difficult due to the necessity of a seal-tight connection.
2. Droplets of impure water are often carried into the condenser portion of the apparatus, particularly at the beginning of the distilling operation, when the water level in the boiling chamber is high; such spillage impairs the purity of the distilled water.
3. The initial time for starting the distilled water flow is relatively long, since the entire mass of water in the chamber must be brought to the boiling point prior to the inception of the distillation process.
One type of distilling apparatus is disclosed in U.S. Pat. No. 4,342,623 (Loeffler). This invention is portable and has an insulated container for raw water and a removable cover for the container, and includes a a low-pressure seal which engages the container wall. A condenser coil is provided in the cover, along with a motor-driven fan; and inlet and outlet ports are provided about the periphery of the cover to allow cooling air to be drawn into the cover over the condenser coil and motor. An inlet tube connected to the condenser coil receives steam generated by a heater connected to the container bottom.
It is evident that stripping and reconnecting the unit for cleaning purposes--a task to be done at least once a week--is quite formidable, owing to the need to install the pressure seal and to scrub the interior of the chamber and the heater.
Another type of water distiller is disclosed in U.S. Pat. No. 4,339,307 (Ellis), which comprises a boiler compartment and a water-filled condenser compartment, combined in one shell, but separated by a partition wall. A condenser coil is disposed in the condenser compartment, and the stream passing therethrough is condensed by the raw water in the upper compartment. A drain valve is provided in the boiler compartment, which should serve to purge impurities collected in the boiler. The water level in the boiler is controlled by a float valve which admits raw water from the condenser compartment, the latter having a similar float valve serving to control its water level. There exists no means for cleaning the bottom of the boiler, and it is evident that sediment will accumulate both in the boiler container, and on the electrical immersion heater. These elements can, therefore, only be removed by complete stripping of the water distiller.
Another portable water distiller is disclosed in U.S. Pat. No. 4,052,267 (McFee), and is characterized by a flexible impermeable bag dividing a cylindrical housing into a vaporating space and a distilled-water space. The steam is condensed in a tubular condenser cooled by an electric fan. The housing is adapted to be separated from the condenser portion for cleaning, and is designed to be subsequently reassembled in a seal-tight connection. By tilting the entire apparatus, distilled water is drawn from the distilled-water space by means of a tap or, in the case of a small unit, through a spout. A raw-water inlet permits filling of the vaporizing space, and a tap near the bottom permits limited access to the housing for cleaning.
McFee also claims a water distiller which comprises a boiler space in the form of a vertical tube positioned inside the impermeable bag. After the bag has been filled with raw water and the electric heater has been energized, the generated steam creates a pressure which presses the water level in the tube to about 5 to 7 inches below the level of the water level in the bag, a pressure which is sufficient to overcome the resistance of the condenser ducts. The bag is provided with an inlet opening for filling with raw water, while steam enters the space contained between the outside of the bag and the inside of the housing where it is condensed into distilled water.
The primary drawback of these embodiments is that cleaning the boiler, the evaporation space, or the electric heater is possible only with complete dis-assembly of the apparatus.
Other water distillers are described in U.S. Pat. Nos. 3,350,279 (Tolchin), 3,935,077 (Dennison), and 4,081,331 (Weiss), all of which disclose devices which are most difficult to clean.
One object of the present invention is the elimination or reduction of these drawbacks by providing a portable water distiller which lends itself to easy removal of residues and sediment by simple manipulation of movable parts.
Another object of the present invention is to provide a distiller which is capable of supplying distilled water within a short time after being energized.
Another object of the present invention is to provide a distilling apparatus with means for filling and drawing water from the reservoir without the need of lifting or tilting the apparatus, a feature which not only reduces the possibility of contamination of the distilled product, but also is more convenient for elderly or handicapped people.
Another object of the present invention is to provide a distilling apparatus devoid of seal-tight connections, components which are apt to deteriorate with time, and which make the dis-assembly of the parts to be cleaned a difficult task--again a feature adapted for the handicapped and elderly, and for the reduction of contamination.
Another object of the present invention is to provide a distiller with means for removing from the water all organic volatiles--prior to the water being fed into the evaporation chamber.
Finally, another object of the present invention is to provide a distiller with an activated charcoal filter adapted to absorb organic matter prior to the water being conveyed into the evaporation chamber.